WPF MVVM 键盘按键事件绑定

<TextBox Text="{Binding LoginName}" Height="35" Canvas.Left="306" TextWrapping="Wrap" Canvas.Top="278" Width="293" BorderThickness="0" MaxLength="20">
<TextBox.InputBindings>
<KeyBinding Key="Enter" Command="{Binding DC_Login}"></KeyBinding>
</TextBox.InputBindings>
</TextBox>